• Journal of the Korean Vacuum Society
• /
• v.8 no.3B
• /
• pp.276-282
• /
• 1999

For the quantitative surface analysis of multicomponent materials, algorithms for the compensation of the matrix effect and surface compositional change by ion beam sputtering must be established and reference materials having certified compositions are necessary. These certified reference material (CRM)s are needed for the improvement of instrument performance, inter-laboratory comparison and quantitative surface analysis. Surface analysis group of KRISS developed alloy thin film CRMs by and ion beam sputter deposition system and in-situ surface analysis system to control the composition of alloy thin films The real compositions of the CRMs were certified by inductively coupled plasma-atomic emission spectroscopy (ICP-AES).

• Korean journal of food and cookery science
• /
• v.5 no.2
• /
• pp.27-34
• /
• 1989

In the present study, the oxidative stability of Korean evening primrose oil (EPO) stored in various conditions, i.e., dark, cool, fluorescent light and daylight irradiation were investigated. Furthermore difference between the compositional content of gamma-linolenic acid (GLA) of EPO and that of alpha-linolenic acid of soybean oil (SOY) undergoing various modes of oxidation was observed. The results of the present study were as follows: More rapid autoxidative reations of EPO than that of SOY in vairous conditions increased in order of daylight, fluorescent light, cool and dark. Espectially, autoxidative rates of EPO increased rapidly on exposure to daylight and fluorescent light. This probably was due to chlorophyll functioned as a photosensitizer resulting in rapid oxidation of the EPO during irrdadiation of light. However, there was no difference between compositional content of GLA in EPO and alpha-linolenic acid in SOY undergoing various modes of oxidation. Therefore, theripid oxidative rate of EPO could be due to the catalytic effect of the chlorophyll on the photoxidation and the free radical reaction of PUFA.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2009.05a
• /
• pp.177-181
• /
• 2009

Compositional gradient CrNx coatings were fabricated using arc ion plating in Ar/$N_2$ gaseous mixture by gradually increasing $N_2$ flux rate from 0 to 120 SCCM. The effect of negative substrate bias on the film microstructure and mechanical properties were systematically investigated with XRD, GDOES, and SEM. The results show that substrate bias has an important influence on film growth and microstructure of gradient CrNx coatings. The coatings mainly crystallized in the mixture of hexagonal $Cr_{2}N$ and fcc CrN phases. By increasing substrate bias, film microstructure evolved from an apparent columnar structure to an equiaxed one. With increasing substrate bias, deposition rate first increased, and then decreased. The maximum of deposition rate was 15 nm/min obtained at a bias of -50V.

• Journal of the Korean Ceramic Society
• /
• v.48 no.3
• /
• pp.205-210
• /
• 2011

The dependence of sulfur redox behavior and its diffusivity on temperature and composition was studied in mixed alkali silicate melts by means of square wave voltammetry (SWV) at different frequencies in a temperature range of $1000^{\circ}C$ to $1400^{\circ}C$. The voltammograms showed two reduction peaks at high frequency but only one peak at low frequency. Irrespective of $K_2O/(Na_2O+K_2O)$, each peak potential due to reduction of $S^{6+}$ to $S^{4+}$ and $S^{4+}$ to $S^0$ moved toward a negative direction with temperature decrease, and the peak current showed a strong dependence on frequency at a constant temperature. However, the compositional dependence of the peak potential showed an inconsistent behavior with an increase of $K_2O$. The mixed alkali effect was not observed in sulfur diffusion. This inconsistency of both peak potential and diffusion for compositional dependence may be derived from the strong volatilization of sulfur in melts.

• Journal of the East Asian Society of Dietary Life
• /
• v.9 no.2
• /
• pp.188-194
• /
• 1999

The present study tested to recommend optimum level of Gastrodia rhizoma and effect on the compositional changes of the lipids in Sprague Bawley rats which were fed control diet adding 5, 10, 15% Dioscorea batatas powder and 5, 10, 15% Gastrodia rhizoma powder for 3 weeks, respectively The contents of moisture. ash, fat, protein and carbohydrate in dried Gastrodia rhizoma were 5.9, 2.7 2.1, 0.9 and 88.4%(w/w) respectively. Concentrations of total cholesterol and free cholesterol in liver were the lowest in the 10% Gastrodia rhizoma group. Concentrations of triglyceride and phospholipid in liver were lower in the 10 and 15% Gastrodia rhizoma groups than in the other groups. Concentrations of total cholesterol, free cholesterol, triglyceride and phospholipid in brain were significantly lower in the group 6, 7 compared to the other groups. Concentrations of triglyceride and phospholipid in kidney were slightly lower in the Gastrodia rhizoma groups than those in the Dioscorea batatas groups.

• Proceedings of the Korean Nuclear Society Conference
• /
• 2003.05a
• /
• pp.244-244
• /
• 2003

• Proceedings of the Korean Ceranic Society Conference
• /
• 2002.10a
• /
• pp.170.1-170
• /
• 2002

• Journal of the Korean Vacuum Society
• /
• v.7 no.3
• /
• pp.176-186
• /
• 1998

Pure Pt, Co and their alloy thin films with three different compositions (Pt66-Co34, Pt40-Co60 and Pt18-Co82) were deposited on Si(100) wafers and proposed as a set of certified reference materials (CRM) for the quantification and standardization of surface compositional analysis. The compositions of the binary alloy thin films were controlled by in-situ XPS analyses and the certified compositions of the films have been determined by ICP-AES and RBS analyses after thin film growth. Through comparison of the compositions determined by in-situ XPS with those by ICP, relatively accurate compositions could be obtained with a matrix effect correction. Standard deviations of XPS and AES round robin tests with the Pt-Co alloy thin films were large up to about 4%. On the other hand, the average compositions of the Pt-Co alloy thin films by two methods were in a good agreement within 1%. The formation of a Pt rich surface layer by ion beam sputtering indicates that the surface modification by preferential sputtering must be understood for a better compositional analysis.

• Journal of the Korean Ceramic Society
• /
• v.56 no.2
• /
• pp.173-177
• /
• 2019

Thermal properties of a SiO₂-B₂O₃-BaO ternary glass system depending on compositional change of BaO have been examined to find a proper sealing material for reversible oxide cells. Glass transition temperature and thermal expansion coefficients increased simultaneously up to 55 mol% of BaO content. The structural role of BaO with regard to the thermal properties has been discussed on the basis of Raman spectroscopy results. Flowability of the glass at sealing temperature has been examined with packed glass powders of 12 mm diameter along with a high temperature optical microscope. The practical sealing property of the glass was also examined with YSZ coated with NiO-yittria stabilized zirconia (NiO-YSZ) and it showed good adhesion without noticeable reaction with NiO-YSZ layer.

• Biomolecules & Therapeutics
• /
• v.10 no.1
• /
• pp.25-31
• /
• 2002

This study was carried out to identify the effect of oxidative stress on the pathogenesis of manganese intoxication. Five rats in experimental group were given with $MnCl_2$intraperitoneally for 4 weeks(4 mg/kg once daily 5 days per week) and another five rats for control group were given with normal saline. In experimental group, manganese concentrations increased significantly in nucleus accumbens by 142% (p<0.05), SOD activities increased significantly by 124%(p<0.01), and MDA concentrations increased significantly 148%(p<0.05) compared with control group. Among fatty acids, total n-6 polyunsaturated fatty acids(PU) increased significantly by 231%(p<0.05) compared with control group. Arachidonic acids(AA) increased by 224%(p<0.05), and these increase were composed mostly of n-6 polyunsaturated fatty acids(PUFA). Among n-3 PUFAs except linolenic acids, eicosapentanolc acid(EPA) decreased significantly by 38%(p 0.01) and docosahexanoic acids(DHA) decreased by 30% p<0.05) compared with control group. Our results suggest that the oxygen free radicals produced by manganese may cause compositional changes of fBtty acids in nucleus accumbens of the rat. Characteristics of fatty acids compositional changes by manganese were the decrease of EPAs and DHAs(n-3 PUFAs), and increase of AAs(n-6 PUFAs). These changes with the increase of MDA, suggest that manganese neurotokxcity is caused by lipid perokidation mediated with oxygen free radicals, especially superoxide radicals.